This invention relates to mechanical control assemblies, and more particularly to push-pull or reciprocating cable assemblies suitable for aeronautical applications.
Push-pull control cable assemblies are used for many systems, e.g. aircraft engines, which must be adjusted from a distance or which are located in hostile environments. These controls frequently have a cable that reciprocates within a casing that supports and protects the cable. Fittings are typically attached to both ends of the cable to connect it to a system to be controlled at one end, and to operating levers, pedals and the like at the other end.
With existing controls of this type, the entire control cable assembly must be removed for repair or replacement, and the cable itself cannot be thoroughly inspected without removal of fittings permanently attached to each end. When these cables fail, they are normally discarded and replaced. To facilitate inspection, repair and replacement, a control assembly with a reciprocating cable that can be removed from the casing without removing or disassembling the casing would be desirable.
This invention provides improved control cable assemblies having control cables mounted within and adapted for reciprocation within an outer casing. A fitting is permanently attached, preferable by swaging or other mechanical deformation process, to at least one end, normally both ends, of the control cable. These fittings have a projected width, i.e. the width in a plane at right angles to the axis of the cable, no greater than the inner diameter of the casing. As a result, the entire control cable, with fittings attached, can be pulled through the casing to remove the control cable for inspection, maintenance or replacement. This simplifies maintenance, and substantially increases the service life of the cable assembly. To facilitate connection to control levers, pedals or the like, or to apparatus to be controlled or operated, couplings or other connecting members may be detachably secured to the fittings by renewable connections such as threaded joints, for example, that allow the couplings to be removed and replaced easily.
The invention also provides a unique combination of ball joint assemblies and excluder seals that effectively exclude contaminants from the interior of the casing, which also helps to increase service life. These and other features of the inventive cable are described more thoroughly in the following detailed description.